Field of the Invention
The present invention relates to an image processing apparatus and method, and, more specifically, to a technique for correcting brightness of an input image.
Description of the Related Art
Upon shooting an image of an object, if the brightness of the object is insufficient, a captured image may be dark. If a gain is applied to the captured image in order to compensate for the brightness of a dark portion of the image, noise is also amplified, and it is difficult to obtain a high quality image. Conventionally, in order to obtain an image with low noise while compensating for the brightness of an object, there is a method of using an illumination device, such as an electronic flash unit, to secure sufficient brightness and shooting the illuminated object. However, the shade of the object will be lost by flashing the illumination device, such as an electronic flash unit, when shooting the image, and the obtained image may look flat with the plasticity of the object being lost.
As a method for shooting an image without losing the plasticity of an object, Japanese Patent Laid-Open No. 2005-167376 suggests a method of shooting a plurality of images under a plurality of illumination conditions, such as illumination positions, using a plurality of illumination devices, such as electronic flash units, and from among the plurality of images, selecting an image with shade.
However, in the method suggested by Japanese Patent Laid-Open No. 2005-167376, it is necessary to shoot an object many times by changing illumination conditions of the plurality of illumination devices. Furthermore, as for images whose shade is lost by using illumination devices when shooting the images, the lost shade cannot be recovered.